The exceptional drought in the U.S. West has people across the region on edge after the record-setting fires of 2020. Last year, Colorado alone saw its three largest fires in recorded state history, one burning late in October and crossing the barren Continental Divide well above the tree line.

Those fires didn’t just feel extreme. Evidence now shows the 2020 fire season pushed these ecosystems to levels of burning unprecedented for at least 2,000 years.

That evidence, which we describe in a study published June 14, 2021, serves as a sobering example of how climate change is altering the ecosystems on which lives and economies depend. A previous study nearly a decade ago warned that by the mid-21st century, climate warming could increase burning past historical levels and transform some Rocky Mountain forests. Our results show such changes in fire activity are now underway.

As paleoecologists – scientists who study how and why ecosystems changed in the past – we’ve spent decades researching how wildfires, climate and forests change over time.

We used to be able to look to the past when rare events like large wildfires occurred and say “we’ve seen this before and our ecosystems have generally bounced back.” In the last few years, however, it’s become increasingly clear that many ecosystems are entering uncharted territory.

We estimated that fires burned the forests around each lake once every 230 years, on average, over the past 2,000 years. Over just the 21st century, the rate of burning has nearly doubled, with a fire now expected to burn a given spot once every 117 years.

Even more surprising, fires in the 21st century are now burning 22% more often than the highest rate of burning reached in the previous 2,000 years.

Read the full article about climate change making Rocky Mountain forests more flammable by Philip Higuera, Bryan Shuman, and Kyra Wolf at The Conversation.